Switchboard-circuit and exchange apparatus for telephones.



H. J. ROBERTS. v SWITGHBOABD GIRGUIT AND EXCHANGE APPARATUS FOR TELEPHONES.

APPLICATION FILED OCT. 13, 1906. 1,000,123. Patented Aug. 8, 191-1.

2 SHEETSSHEET 1.

COLUMBIA PMNOGRAPH CD WASHINGTON, D. C.

H. J. ROBERTS. SWITGHBOARD CIRCUIT AND EXCHANGE APPARATUS FOR TELEPHONE-S.

APPLICATION FILED OCT 13, 1906. 1,000,123, A Patented Aug. 8,1911.

2 SHEETS-SHEET 2.

COLUMBIA PLANOURAPH C0. WASHINGTON. D. C

UNTTED STATES PATENT OFFICE.

HOMER J. ROBERTS, 0F EVANSTON, ILLINOIS, ASSIGNOR, BY IVIESNE ASSIGNMENTS, TO HOMER ROBERTS TELEPHONE 00., A CORPORATION OF WEST VIRGINIA.

SWITCI-IBOARlD-CIRCUIT AND EXCHANGE APPARATUS FOR TELEPHONES.

Patented A11 8, 1911.

Original application filed September 5, 1905, Serial No. 276,975. Divided and this application filed Qctober T 0 all whom it may concern:

Be it known that I, HOMER J. ROBERTS, acitizen of the United States, residing at Evanston, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Switchboard-Circuits and Exchange Apparatus for Tele phones, of which the following is a specification filed as a divisional application of my original application filed September 5, 1905, Serial No. 276,975.

This invention relates to improvements in switchboard circuits and exchange apparatus for telephones, and it has for its general object the production of a system suitable for switchboards handling both selective party-lines and individual lines and embodying two systems of signals.

More specifically the salient object of the invention is to provide a switchboard system and apparatus in which there is combined in a party-line system a calling in or drop signal system and a supervisory or clearing out signal system.

The invention also has for its object the provision of a system of the general character referred to so organized that all of the cord pairs of a given section may be used in common, 2'. c. indiscriminately, for making connections with both party-lines and individual lines.

To the above ends the invention consists in the matters hereinafter described and more particularly pointed out in the appended claims.

The invention will be readily understood from the following description, reference being had to the accompanying drawings forming a part thereof, in which Figures 1 and 1 taken together represent diagrammatically the complete switchboard circuits and operating mechanism.

In the particular embodiment of the invention illustrated, it is designed for use in a switchboard which has both selective party-line subscribers and individual line subscribers; the selective party-lines being of that type in which the selections are performed by counting out a definite number of impulses of current of one polarity and the ringing of the selected party effected by throwing onto the line pulsating current of Serial No. 338,685.

a polarity opposite that employed in the selecting.

In the present system two sets of signaling apparatus are embodied, one controlling the line drops and operated by common battery, the other controlling self-restoring supervisory signals and also operated by common battery. The supervisory signals are inclividual to the several pairs of cords so that they are severally in use only as their corresponding cords are in use.

In practice, in adding to an ordinary manual exchange switchboard already installed selective party-lines, the cord keys already installed may be and usually are utilized by simply adding additional pairs of contact strips and additional bus-lines connecting each of the cord keys so converted to the master-key set. Thus arranged, the operator desiring to use any given pair of cords for connecting between two party-lines, or between one party-line and an individual line, simply places the key controlling that pair of cords in its selfretaining position and thereafter performs the further work of completing the connections through the master-key, as well as the operation (which is usually necessary in lock-out party-line systems) of clearing, 0'. e. restoring the line to normal.

Referring now to the diagram, A, A, A designate a plurality of cord keys, and B, B, two somewhat similar keys which latter together constitute the complete master-key set.

C designates diagrammatically a source of usual alternating calling current, the generator shown being connected by bus-lines 1 and 2 with the several cord keys.

D designates as a whole diagrammatically a generator so arranged as to afford pulsations of either polarity.

E designates as a whole an automatic pulsation-counter, which for convenience of description will be herein termed a selector; its function being to count out a definite number of pulsations and in this manner effect selection of the particular party wanted on a party-line.

F designates a main battery, which affords current for various purposes, and G a second battery of a less number of elements which supplies current for both signaling systems.

H, H, H designate a plurality of springjacks forming the terminals of corresponding metallic lines, and I, I, 1 corresponding line drops.

Each cord key is provided on each side with inner pairs of contacts, as 3, 3, 1, 4t and 5, 5 and 6, 6, which, in the intermediate position of the key, are closed. The springs 8, 4t, 5 and 6 are respectively connccted with the tip and sleeve sides of the cords, as 7, 8, 9 and 10, and are shifted into contact with outer springs 11, 12, 13 and 14, respectively, when the key is shifted in one direction or the other. Of these latter springs, 11 and 12 are connected with the bus-lines 1 and 2, respectively, while the springs 13 and 14 are connected with another pair of bus-lines 15 and 16, respectively. These latter lines lead to the masterkey and, as will be seen by tracing the circuits, connect the master-key with the answering cord sides of the several keys A, A, A The additional springs which are added to each key are indicated at 17, 18 and 19, 20, respectively; the moving members 18 and 19 being connected with but insulated from the corresponding springs 13 and 14. Springs 18 and 19 are respectively connected with the left and right sides of another pair of bus-lines 21, 92, while the cooperating springs 17 and 20 are respectively connected with the innermost springs 3, 41 of the opposite side of the key and also with the innermost springs 5, G of the same side of the key. A condenser 23 is interposed in the connection leading from spring 17 to spring i. e. from the tip side, for a purpose whlch will hereinafter appear. The connections of each key A, A, A are precisely similar.

Referring to the master-key set, the key B is so organized that when shifted in one direction (downwardly, as shown) it throws current through the selector E and to the answering cord of whatever cord key is in use and shifted to a self-retaining position. Similarly when key B is shifted in the opposite direction it throws current through the selector E to the connecting cord of the same cord key. In either of the shifted positions of key B the current sent to line may be pulsating positive or pulsating negative, depending upon the position of the selector E. That is to say, the selector E when rotating sends current of one polarity to line but as it reaches its normal or zero position it reverses to connections and sends current of opposite polarity to line. It will be seen from the foregoing that key B is utilized for calling the subscribers.

Connected with key B so as to move positively in both directions with the latter is a subsidiary key B which is so constructed as to shift the springs controlled thereby whenever 1t moves in either direction. This key performs various functions as will hereinafter appear, chief among which. being the control of the battery connections.

Key B is so organized as to place the main battery F which is of relatively large capacity directly to the left-hand side of the line and at the same time to ground at the opposite side of the battery; the shift ing of the key in one direction (downwardly, as shown) serving to throw the main battery direct to the answering cord and the shifting of the key in the opposite direction sending the current to the connecting cord. Connected with key B is a subsidiary key B similar to the subsidiary key B but so connected that it moves with key B in one direction only, namely when the latter key is shifted upwardly. The mechanical connection whereby this is effected is indicated at 24 wherein the stem of key B telescopes within a sleeve connected with key B; the end of the stem of key B terminating in proximity to the body of key B. Key B is provided with a stem and push button whereby it may be depressed and when so depressed it obviously forces with it key B. The functions of key 3 are in general similar to those of key B". An auxiliary push button J is pro vided which is mounted on one end of a lever pivoted at the opposite end of the lever being operatively connected with the stem of key member 13. The push button J controls a group of contacts which throw pulsating current of one polarity from the generator D direct to the line through the answering cord.

In the particular party-line system for which the present invention is in this instance specifically ada-pted, any subscriber who calls in is located and connection given him by looking out all stations bet-ween his set and central, and this locking out is effected by operating the relays at the several stations one after another by a. series of pulsations thrown to line through push button J. Since this operation is in elfect running down the line until that station is reached from which the subscriber has called, the push button J will be designated the running key. A call for connection coming in over a subscribers party-line would throw the line drop, as for example at 1, whereupon the operator would insert a plug of any available answering cord and secure talking connections and take the order from the calling subscriber as follows: Observing that the call was on a party-line she would shift the cord key to its self-retaining position, thus extending the circuits from the spring jack over conductors 9, (rand 13 to bus-line 15 and over conductors 10, 6 and 14 to bus-line 16, thereby extending the connections to the masterkey set. Bus-lines 15 and 16 are connected with the master-key set through conductors 26 and 27, and the circuit closed by the running key in responding to the subscribers call may be traced as follows: over line 26 to intermediate spring 28 of key B, inner spring 29, conductor 30 to intermediate spring 31 of running key, to back spring 32, thence over conductor 33 to conductor 31, from the latter over conductor 35 to the pole changer, from the pole changer over conductor 36 to front spring 37 of the selector, thence to the intermediate spring 38, from the latter over conductor 39 to a contact arm 10, thence over conductor 11 to conductor 34; which connects by conductor 12 with the back contact 32 of the running key, which is at this time closed with intermediate spring 31. The latter, as hereinbefore described, is connected with conductor 27. This conipletes the circuit. The result of throwing pulsations of one polarity over the circuit described is to lock out the subscribers suc cessively until the subscriber is reached who called for the connection. By operating his switch-hook or some other suitable act the subscriber places his set in such condition that succeeding impulses, after his in strument has been reached, will fail to pass the same. But although he thus arrests the further selection it is necessary to put one or more impulses of opposite polarity through his set in order to place the same in talking circuit. This reverse polarity impulse is sent over the line by shifting key B downwardly, which results in transposing the connections between the generator D and the line. This reverse is not made until an ample number of impulses have been sent out to more than reach the substation; the excess impulses being inefiectual. That part of the circuit which is reversed may be traced from the generator over the conductor 35 to line 34, thence to outer spring 13 of key B, thence to switch spring 4 1, over conductor 15 to inner spring -16 of the running key, to switch spring 31, thence over line 27 to bus-line 16, which is connected through the cord key to the sleeve side of the line. From the other side of the generator the circuit is over conductor 36, springs 37 and 38, conductor 39, arm 10, conductor etl to spring 43 of key B, thence to switch spring 1% and thence to inner spring 16 of the running key over con ductor as. From spring 46 the circuit is through spring 31, thence over conductor 30 to and through springs 29 and 28 of key B and to bus-line 15 over conductor 26.

In the self-retaining position of the cord keys the exchange operators set is in listening connection with both ends of the cord. The listening connections with the answering end of the cord may be traced from bus-lines 15 and 16 as follows: over conductor 26, springs 28, 29, conductor 30, springs 31 and 16 of the running key, conductor 15, springs 1 1 and an inner spring 4E8 of key B, through a condenser 49, thence over a conductor 50 to the tip side of operators jack 51. The other side is over conductor 27, springs 31 and 16 of the running key, con ductor 15 to switch spring 44: and inner spring 18, thence through condenser 19 and over conductor 50 to spring 52 of key B", to spring 53 and back over conductor 54: to the sleeve side of the operators jack. The listening circuit connections with the calling end of the cord are from bus-line 21 over a conductor 55, to switch spring 56 of key B, to inner spring 57, thence over conductor 58 to switch spring 59 of key B, thence to inner spring 60, and thence overconductor 61 to conductor 50 and to the tip side of the jack. Similarly from bus-line over conductor 62 to switch spring 59, inner spring and thence to the sleeve side of the jack as before traced.

The operator, having answered the subscriber, takes his order for a connection. It a party on an individual line were wanted the connections would be made by simply inserting the connecting or calling end of the cord in the proper jack and shifting the cord key into its reversed position, thereby throwing ringing circuit from the bus-lines 1 and 2 through the called subscribers bell. If, however, a party-line connection is called for, the next operation will be to insert the connecting end of the cord in the proper jack and select and call the particular party wanted. The first operation, after inserting the plug, will be to set the selector dial to throw upon the line as many impulses (which are automatically counted out by the selector instrument) as will efiect the selection of the right party. The selector E is so constructed that the dial and connected ratchet are spring-returned to the zero position, and the returning movement is con trolled by a magnet K the armature 7a of which constitutes an escapemcnt lever. By means of a suitable handle the dial is 1nanu ally turned forwardly as many notches as will correspond w'th the number of the party wanted counting the sub-stations outwardly from central. The magnet escapement permits the dial to return one notch for each impulse, and as the dial reaches the zero position it is arrested by a stop-pin 63 engaging a suitable stationary stop 64. Cams 65 and 66 are mounted upon the ends of the respective switch springs 38 and 38 of the selector, and these cams in the zero position. of the dial rest in recesses 67, 6.7, respectively formed in an insulated hub 68 carried on the shaft of the selector and rotating wit-h the ratchet of the latter. As soon as the dial is moved away from the Zero position these cams are forced out of the V-shaped recesses and thereafter ride upon the periphery of the hub, thus moving the switch springs 38 and 38 outwardly into bearing with back contact springs (39 and 70, respectively. The shifting of the switch springs in this manner reverses the connections with the pole changer I), so that while selecting impulses are sent to line during the return of the selector to Zero, when the selector reaches Zero impulses of opposite polarity or ringing current are sent to llne. Pressing the key B upwardly shifts lts switch springs 59 and 59 outwardly into contact with outer springs 71v and 71, and these springs are connected with conductors 34 and 34-, respectively, so that impulses are sent to line in substantially the same manner as when operating the running key.

A. local circuit is closed through and operates the magnet K when the key B is closed in either direction, (provided the selector has been set) which current may be traced as follows: from the generatoi through conductor 36 and spring 38' to back contact 70, thence over a conductor 72 to and through the magnet K, thence to a switch spring 73 pertaining to key B, from the latter to cooperating spring 74:, which spring is connected with conductors 34L and 35, which lead back to the opposite side of the pole changer.

In the present invention a system of supervisory signals is provided which notifies the exchange operator whenever either party has ceased talking and hung up his receiver, thus indicating that the line should be cleared. The subseribers set is so organized that hanging up the receiver closes a full metallic bridge at his station; it being understood that the talking circuit at the subscribers station is through a condenser so that battery cannot flow. Describing this supervisory system, 75 designates a bus line, and between this bus-line and the answering end of each cord is interposed a self-restoring signal 76; the conductors 7'7 in which these signals are interposed being connected withthe sleeve side of the respective answering ends of the cords. Line 75 extends to and is connected with switch spring 78 of key 13. This spring normally engages inner spring 79 which is connected by conductor 80 with the innermost spring 81 of key B. This is normally closed with an opposed spring 82 which is connected by conductor 83 with signal battery G. The opposite side of the battery is connected to a conductor 84 which forms a busline common to all of the line drops I, I, I, etc., the latter being severally interposed between line 84: and the tip springs of the corresponding jacks. It follows that whenever the subscriber connccted with the answering end of the cord hangs up his receiver, the self-restoring signal 76, pertaining to the cord in use, is energized and indicates the line should be clear.

At this point itmay be explained that the line drops are operated by the battery G at central and that said operation is effected by grounding the line at the subscribers station. Ordinarily a flash ground eifected during the upward movement of the switch hook is employed to throw the line drop. T he connection from line 8-1- through the battery G to ground is over conductor 83, spring 82, switch spring 73, a conductor 85 to an inner spring 86 controlled by key B", from the latter to switch spring 78, thence by conductor 87 to a conductor 88 which connects the two switch springs 50 and 28 of key B with each other and to ground at 89 over a conductor 90.

Inasmuch as those subscribers between central and the party selected are locked out in the act of selecting the latter, it follows that means must be provided for clearing or restoring the look-out instruments to normal. As much of the subscribers circmt as is necessary to understand this operation is shown at L and M at the foot of Fig. l; the party-line being shown connected with the spring jack H. The clearing of the lines is efl'ected by closing a ground-to-ground circuit from central at one end through the main battery at central, over the left or tip side of the subscribers line through the several clearing relays which are in series with said left line and to ground at the last subscribers set. At the remote end of the left-hand line is located a circuit-catching instrument N comprising a condenser 100, a magnet 101 in series with the condenser and connected to ground at 102, and a shunt conductor 103 which leads around the condenser to an armature 101 which, when in closed position, engages a contact 105 connected with a few of the coils of the main magnet in such manner as to form a self-retaining circuit. It is necessary to clear both the calling and called subscribers if both are party-lines, and the key B is so constituted as to effect clearing of the answering end of the cord when shifted downwardly, and the connecting or calling end when shifted in the reverse direction. rissuming the calling subscribers line is to be cleared, the circuit will be from ground at 89 to switch spring 28, back spring 91, conductors 92 and 93 to battery F, thence by conductors 94 and 95 to back spring 91 and switch spring 28, which latter is connected by conductor 26 with the bus-line 15. Line 15 is connected with the tip side of the answering end of the cord through springs 13, 5, and conductor 9. In case the called subscribers line is to be cleared, the circuit will be from ground at central through the battery over conductors 90 and 88, to switch spring 56, thence to back spring 96, to conductors 92 and 93 to battery, from battery over conductor 9% to 95, and to backspring 96, thence to switch spring 56 and from the latter to bus-line 21 over conductor 55. Bus-line 21 is connected with spring 18 and engages spring 17 which is connected by a conductor 3 with the inner spring 3 of the cord key. Spring 3 is at this time closed with spring 3 which is connected by conductor 7 with the tip side of the plug.

In the operation of the master-key set, it is necessary that ground be cut off at central when ringing impulses are sent to line; it is necessary that the supervisory signal and line drop circuits be protected against the main battery and generator D when clearing and ringing and it is desirable that the exchange operat-ors set be either short circuited or opened before either the main battery or pole changer circuits are thrown upon the line, in order to prevent reports in the operators ear. It is the function of the supervisory keys 13 and B to effect these results. In case the running key J is depressed, the ground at 89 is opened between the springs 78 and 86 of key B and in case the key B be shifted in either direction those same contact springs cut oi the main battery F from the conductor 85 which is a part of the line drop circuit. In a similar manner movement of key B opens the circu1t between springs 7.8 and 79 which form part of the supervisory circuit. For the same reasons and in the same manner springs 78 and 82 open the line drop circuit at key B, and springs 81 and 82 at the same key open the supervisory circuit. Movement of key B opens the operators listening circuit between the springs 52 and 53, while movement of key B" eiiects the same result of preventing a report in the operators receiver by short circuiting the operators jack through the springs 97 and 98 and the conductors connected therewith.

A resistance coil 107 interposed in a conductor 106 placed across the two limbs of the circuit at the pole changer permits a leakage across and over the external circuit during the time main impulses are passing through the selector and neutralizes residual magnetism.

I claim as my invention:

1. In a telephone system, the combination with a switchboard, of a plurality of lines terminating in said switchboard, a. plurality of connecting cords and corresponding cord keys controlling said cords, a. clearing out signal for each cord, circuit connections whereby said clearing out signals are operated when the circuit is closed, and contact devices included in said circuit connections and operating to complete the signaling circuit when closed, said contact devices being directly and mechanically closed by the returning of the subscribers switch hook to normal, and remaining closed while the switch hook is in normal position.

2. In a switchboard system, the combination with a plurality of subscribers lines, each terminating in a connection jack, of a switchboard bus-line provided with multiple branches severally extending to and connected with one of each line jack, a line drop interposed in each of said multiple branches, a battery in said bus-line, a plurality of cord circuits, a second bus-line common to said several cord circuits and provided with multiple branches severally extending to and connected with one side of each cord circuit, and clearing out signals interposed in each of said latter multiple branches whereby the line drop of a given jack and the clearing out signal pertaining tothe cord connected with said jack are in service connection simultaneously.

3. In a switchboard system means for simultaneously placing battery on the external lines and bringing into service a supervisory signal, comprising a plurality of subscribers lines each terminating in a connection jack at the switchboard, a plurality of cord circuits, a bus-line-provided with multiple branches severally connected with one side of each cord circuit, a supervisory signal interposed in each of said multiple branches, a second bus-line connected to and forming an extension of said first bus-line and provided with multiple branches severally connected with each connection jack, and a battery connected with said bus-lines whereby upon the plugging in of a given cord the switchboard endof the circuit is completed and the corresponding supervisory signal included, in a closed circuit when in operative condition.

4. In a switchboard system, the combination with a plurality of subscribers lines terminating in line jacks at the switchboard, of a plurality of connecting cords, each cord comprising a. pair of connecting terminals or plugs and cord keys arranged to control the several cords, a line drop for each line jack, a supervisory signal for each cord circuit, a bus-line connecting the line jacks and cord pairs and including the line drops and supervisory signals, whereby the line drop of a given jack and the clearing out signal pertaining to the cord connected to said jack are in service connect-ion simultane ously.

5. In a switchboard system, the combination with a plurality of subscribers lines, each terminating in a connection jack, of a plurality of connecting cords and corresponding cord keys controlling said cord, a line drop for each connection jack, a busline connected to the respective line jacks and cords and including said line drops,

clearing out circuit connections at the switchboard, a master key set controlling the various circuit connections, and contact devices included in said busline and controlled by said master key.

6. In a switchboard system, the combination with a plurality of subscribers" lines, each terminating in a connection ack, of a plurality of connecting cords and corresponding cord keys controlling the same, a bus-line connected to the respective cords and line jacks, a supervisory signal for each cord connected to said bus'line, clearing out circuit connections at the switchboard a master key set controlling the various circuit connections, contact devices included in said bus-line and controlled by the master key whereby said supervisory signals are automatically cut off the line upon clearing the latter.

7. In a switchboard system, the combina tion with a plurality of subscribers lines, each terminating in a connection jack of a plurality of connecting cords and corresponding cord keys controlling said cords, the bus-line connecting the respective cords and line jacks, line drops and supervisory signals for the respective line acks and cord pairs connected to said bus-line, contact devices included in the bus-line circuit.

HOMER J. ROBERTS. lVitnesses ALBERT H. Gnavns, EMILIE Rosa.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

